We have a common pattern here in nixpkgs for Python applications: when a
Python package ships with either a requirements.txt or setup.py file, we
generally end up having to modify its version restriction, otherwise we have
build failures since we package only one specific version of each package
normally.
However, this end up being done in a completely ad-hoc way: some people
use substituteInPlace, some others use sed, others uses patches, etc.
In many cases, the code ends up being buggy, so it may work in one
version and breaks on the next one. We can instead implement one
standard way of doing this, and trying to be a correct as possible.
So this is what this commit does: it implements a new build hook, that
when called will automatically patch the wheel file. This is one of the
most generic ways to patch Python dependencies, and should work in
multiple cases.
Noticed option globbing when tried to enable parallelism by default
locally for most packages by default. python3Packages.yt-dlp failed as:
python3.9-yt-dlp> /nix/store/5mywvxdjkk1q6srwwwgdkzc37ibla801-python3.9-setuptools-61.2.0/lib/python3.9/site-packages/setuptools/dist.py:516: UserWarning: Normalizing '2022.04.08' to '2022.4.8'
python3.9-yt-dlp> warnings.warn(tmpl.format(**locals()))
python3.9-yt-dlp> invalid command name 'build_lazy_extractors--parallel'
The change adds leading whitespace everywhere where options might
already be present.
Overriding the interpreters did not work correctly. When overriding
packages would end up twice in the build time closure: one corresponding
to the overridden interpreter and one corresponding to the original
interpreter. The reason is that the override was not applied to the
interpreters in the spliced package sets.
Malo Bourgon